Not Applicable
Not Applicable
1. Field of Invention
This invention relates to a blanket for covering it least a portion of the body of a human, or other animal, in order to bath the body portion in a conditioned gas. More specifically, the present invention is related to an inflatable thermal blanket for providing a conditioned gas, such as, for example, heated air, to a portion of the body of a user.
2. Description of the Related Art
Inflatable thermal blankets which are used to communicate a conditioned gas, such as heated or cooled air, to a patient are known in the art. Such thermal blankets typically have an inflatable portion provided with an inlet port for placing the inflatable portion in fluid communication with a source of pressurized, conditioned gas such that the inflatable portion can be selectively inflated. The inflatable portion generally has an inner surface which is gas pervious, or which is otherwise adapted to communicate the conditioned gas used to inflate the blanket to the user. Such thermal blankets are often used to treat conditions such as hypothermia, or used to reduce the body temperature of a user in circumstances where the body temperature is inappropriately high. For example, where a patient is being treated for hypothermia, at least a portion of the patient""s body is covered with the thermal blanket, and warm air is pumped into the inflatable portion. The warm air used to inflate the inflatable portion is thereafter communicated through the inner surface of the inflatable portion so as to bath the body portion covered by the blanket in warm air. Examples of such thermal blankets are disclosed in U.S. Pat. Nos. 5,184,612; 5,304,213; and 5,324,320. Whereas prior art thermal blankets serve to deliver conditioned air to a patient, the temperature of the air being communicated through the inner surface of the inflatable portion, and the surface temperature of the inner surface, can vary greatly over the area of the inner surface. For example, if heated air is pumped into the inflatable portion through the inlet port, the air within the blanket near the inlet port tends to be substantially higher in temperature than the air within the blanket which is remote from the inlet port. Accordingly, the inner surface of the blanket proximate the inlet port, and the air communicated to the patient through the inner surface of the blanket proximate the inlet port, can be uncomfortably, or damagingly, hot when the blanket is otherwise communicating air of the desired temperature to the patient. Whereas the temperature of the air entering the inlet port can be reduced to avoid uncomfortable, or damaging, hot spots near the inlet port, such a reduction of temperature can compromise the overall effectiveness of the thermal blanket.
Other devices for warming or cooling patients, and/or for communicating conditioned air to a patient, are disclosed in U.S. Pat. Nos. 1,777,982; 2,093,834; 3,653,083; 4,347,633; 4,472,847; 4,572,188; 4,660,388; 4,777,802; 5,106,373; 5,165,400; 5,300,101; 5,300,102; 5,336,250; 5,350,417; 5,405,371; 5,545,194; 5,674,269; 5,860,292; 6,102,936; 6,210,428 B1; and 6,228,107 B1. See also, PCT International Application No. PCT/US85/00071, and British Patent Nos. 716,746; 1 334 935; and 1 566 207.
The present invention provides an inflatable thermal blanket for providing a conditioned gas, such as, for example, heated air, to at least a portion of the body of a human or other animal. The thermal blanket includes an inflatable portion for receiving the conditioned gas under pressure and for being positioned over at least a portion of the body of the user. The inflatable portion is defined by a base sheet which is fabricated of a gas pervious material, or which is otherwise adapted for communicating the conditioned gas to a portion of the body, and defines an outer sheet which is substantially gas impervious. The inflatable portion also includes an inlet port for placing the inflatable portion in fluid communication with a source of conditioned gas, and is constructed so as to define at least one outer channel communicating with the inlet port and one or more inner channels communicating with the outer channel. The inner channels are formed in part by the base sheet such that conditioned gas within the inner channels is communicated through the base sheet to the body of the user. The outer channel is formed at least in part by the outer sheet and an interior wall, or baffle, such that one or more of the inner channels is disposed between the outer channel and the body of the user when the blanket is in use. Accordingly, the conditioned gas that is received through the inlet port is dispersed into the outer channel before being communicated to the inner channel. Thus, the conditioned gas is allowed to disperse, and the temperature of the conditioned gas is allowed to moderate, before it is communicated to the inner channels, thereby reducing temperature variations over the inner surface of the inflatable portion.